Oil-water separator system with oleophobic fibrous filter

Abstract

An oil-water separator system and method to separate contaminated oil and water into clean water and free coalesced oil for collection and removal. The system includes a process tank for the oil and water, a pump to pump the oil and water through first and second stage oil-coalescing filters and through a full depth, fibrous filter under back pressure to provide filtered clean water of selected purity; typically, less than 20 ppm. The coalesced and filtered oil-water is returned and recycled to the process tank wherein a free coalescing oil layer forms on the surface, which free coalesced oil is removed by a belt skimmer for collection and removal.

What is claimed is: 
     
       1. An oil-water separator system to separate contaminated oil-water into clean water and free coalesced oil, which system comprises: a) a process tank to receive and contain oil-water to be separated;   b) an inlet means to introduce oil-water to be separated into the process tank;   c) a pump to pump oil-water from the process tank;   d) an oil-coalescing filter means in a housing to remove particulates and to coalesce oil in the pumped oil-water in the housing;   e) first conduit means to discharge coalesced oil from the coalescing housing into the process tank to form a free coalesced oil layer;   f) a fibrous, depth, oleophobic filter means in a filter housing to receive pumped, filtered oil-water from the coalescing filter means and the pumped, filtered oil-water to sweep the outside of the oleophobic filter means and to provide filtered clean water of selected purity for discharge, and repelled oil-water in the oleophobic filter housing;   g) second conduit means to discharge the repelled oil-water into the process tank;   h) flow control valve means in the second conduit means to control the flow of repelled oil-water to the process tank and to provide back pressure in the upstream side of the oleophobic filter means;   i) discharge means to discharge said filtered clean water from the oleophobic filter means; and   j) oil removal means to remove the coalesced, free oil layer from the oil-water surface of the process tank.   
     
     
       2. The system of claim 1 wherein the oil-coalescing filter means comprises a first stage filter of above 25 microns and a second stage filter of about 1 micron or lower. 
     
     
       3. The system of claim 1 wherein the coalescing filter means comprises a glass fiber, resin-bound, cylindrical depth filter. 
     
     
       4. The system of claim 1 wherein the coalescing housing and the oleophobic filter housing are inverted to permit the collection of coalesced oil at the top of said housings. 
     
     
       5. The system of claim 1 wherein the oleophobic filter means comprises a filter having a filter range of about 0.1 to 1.0 microns. 
     
     
       6. The system of claim 1 wherein the oleophobic filter means comprises a glass fiber, fluorocarbon, resin-bound cylindrical filter. 
     
     
       7. The system of claim 1 wherein the discharge means includes a flow meter to monitor the concentration of oil in the filtered clean water prior to discharge. 
     
     
       8. The system of claim 7 wherein the discharge means and flow meter provide for the discharge of filtered clean water of about 20 ppm or less of oil. 
     
     
       9. The system of claim 1 wherein the oil removal means comprises a timed oil removal belt skimmer means to collect and discharge the free coalesced oil layer from the process tank. 
     
     
       10. The system of claim 1 wherein the first conduit means includes an orifice to force the oil-water through the oil-coalescing filter means. 
     
     
       11. The system of claim 1 which includes a source of contaminated oil-water to be separated and connected to the outlet means, the oil-water source containing oil-water with hydrocarbons, diesters, and polyglycols. 
     
     
       12. The system of claim 1 wherein the depth oleophobic filter means has a depth of about 1/8 to 1/2 inch. 
     
     
       13. The system of claim 1 wherein the oleophobic filter means comprises a tetrafluoroethylene polymer bound and coated glass fiber filter.